1. Field of the Invention
The present invention relates to a lubricant supplying device, a cleaning device, a process cartridge, and an image forming apparatus.
2. Description of the Related Art
In an electrophotographic image forming apparatus, such as a copier, a printer, a facsimile machine, and a multifunctional product (MFP) using a combination thereof, a lubricant supplying device (lubricant applicator) has been employed. The lubricant supplying device supplies (applies) lubricant to an image carrier to reliably remove attachments such as non-transferred toner on the image carrier such as a photosensitive drum by a cleaning device and reduce abrasion of the image carrier and a cleaning blade. For example, Japanese Patent Application Laid-Open No. 2002-62737 discloses such a technology.
Specifically, all of the non-transferred toner left on the image carrier after a transferring process have to be removed by the cleaning blade (cleaning device) abutting on the image carrier. However, when the cleaning blade is deteriorated (abraded) with time due to the abutment on the image carrier, the non-transferred toner may go through a gap between the abraded cleaning blade and the image carrier to cause defective cleaning. Even if the cleaning blade has not yet been deteriorated, when a small-particle-diameter toner or spherical toner is used, the toner may enter and then go through a slight gap between the cleaning blade and the image carrier to cause defective cleaning. Furthermore, when the toner and the attachments, such as an external additive included in the toner and paper powder, go through the gap between the cleaning blade and the image carrier, they may be fixed on the image carrier in a film shape to cause filming.
To overcome these problems, lubricant is applied to the image carrier. With this, a coefficient of friction on the image carrier is decreased to reduce deterioration of the cleaning blade and the image carrier. Also, the capability of detachment of attachments, such as non-transferred toner, from the image carrier is increased, thereby preventing the occurrence of defective cleaning and filming due to changes with time.
Specifically, in the above conventional technology, for example, the lubricant supplying device includes a brush-shaped rotating member (brush member), a solid lubricant abutting on the brush-shaped rotating member, a spring that presses the brush-shaped rotating member onto the fixed lubricant, and others. Being gradually scraped off the solid lubricant by the brush-shaped rotating member rotating in a predetermined direction, lubricant scraped off by the brush-shaped rotating member is applied to the surface of the image carrier.
On the other hand, for example, Japanese Patent Application Laid-Open No. 2005-70276 discloses a lubricant supplying device with a container accommodating lubricant being disposed near an image carrier and a technology of directly supplying the lubricant accommodated in the container to the image carrier.
Besides, for example, Japanese Patent Application Laid-Open No. H11-65311 discloses a technology in which a lubricant supplying device is provided above an image carrier to supply lubricant onto the surface of the image carrier through a free-falling of the lubricant scraped by a brush-shaped rotating member.
In the conventional technology disclosed in Japanese Patent Application Laid-Open No. 2002-62737, the brush-shaped rotating member directly abuts the image carrier. Thus, a flaw tends to occur on the surface of the image carrier, and it is difficult to increase the life of the image carrier.
In contrast, in the conventional technology disclosed in Japanese Patent Application Laid-Open No. 2005-70276, no brush-shaped member is provided, and the lubricant accommodated in the container is directly supplied. Thus, a flaw tends not to occur on the surface of the image carrier. However, a large amount of lubricant is always in contact with the image carrier, the lubricant may possibly be excessively supplied to the image carrier more than a required amount.
In the conventional technology disclosed in Japanese Patent Application Laid-Open No. H11-65311, a bush-shaped rotating member is distanced from the image carrier. Thus, a flow tends not to occur on the surface of the image carrier. However, the lubricant scraped by the brush-shaped rotating is let freely fall to be supplied onto the surface of the image carrier. Therefore, the lubricant may be supplied only to a part of the surface of the image carrier to cause unevenness in supplying the lubricant. Moreover, in such a technology of supplying the lubricant onto the image carrier by free-falling, it is difficult to control the amount of supply of the lubricant to be supplied onto the image carrier and its supply timing. Specifically, even when the lubricant is not desired to be supplied onto the image carrier, the lubricant may be supplied onto the image carrier by free-falling. Furthermore, since the configuration is such that the lubricant is supplied onto the image carrier by free-falling, the lubricant supplying device has to be disposed above the image carrier. Therefore, the restriction by the layout of the image forming apparatus is significant.